ORIGINAL: tsbpenguin

Ok where to start. The garrett turbo's don't produce more power than k04's, they just have a higher airflow capacity which allows for the potential for more power. GT28R's, from everything i've heard, have no problem fitting in the stock location.

Im sorry they put more air in the engine so more fuel can be burned in a smaller ammount of time. Combusting more fuel breaking the chemical bonds in the hydro-carbons in more molecules releasing energy, thus converting more chemical energy to heat energy then mechanical energy. Sounds like more power to me....

As for intercoolers, and good dp's, are you honestly telling me you wouldn't want to run these on a k04 setup? Stock or low flow dp's will kill the k04's and then you just wasted even more money.

There ARE people with k04's that have stock dp's/piggies and stock intercoolers. There is no one with garretts without upgraded downpipes and intercoolers. And yeah i would want to run them, read my last paragraph. Before k04's i will have AWE Dp's and Evolution Racewerks intercoolers, dosnt mean you have to though... And i stay by my statement, with K04's you can retain many of the stock engine components, when you get garretts you sure as hell better build up the motor unless you wanna shell it....

Stock s4 fuel is good to a certain point but again, with k04's you're going to want to replace the fuel system anyway. If you run it on your stock fuel system, at it's capacity, something's likely to go out.

$5500 AWE kit comes with fueling.

Clutch and brakes. Brakes are essential with pretty much any mods. Anyone will realize this their first time trying to slow down from 140-170mph. And you think the stock clutch will hold up to k04's? Keep dreaming. 400hp from your k04's is going to tear up an oem clutch almost as fast as the 500-600hp from the gt28r's.

I said from stage 2+ like i am, i have an rs4 clutch. Planning on brakes.

I'm not saying they're for everyone. I'm just saying I don't see why more people with a little DIY skill don't take on the gt28r project. It's really no different or more expensive than a k04 project.

It is more difficult, and thats why its more expensive. More power means you break more, they key is that k04's are OEM RS4 parts so audi has done much of the design and development themselves. It just took independent companies to come up with a kit. Also when tuning the s4 im sure companys used the rs4 file as a sort of template before modifing it, much easier than a complete custom tune. Audi would never push a production v6 to 600whp

ORIGINAL: 2k S4

If over 400w torque & a full STREET car in the 11's is to slow, then just get another car......

ORIGINAL: Baskin 4.2l

WOW Way off and obviously not researched. Ko4's gas out at about 470whp on racegas(depending on dyno)

GT28 turbos make about 500whp on pump gas. Push big boost and race gas and from what I have know they make over 600whp or more

There are several company's that are progressive. I chose VAST because of there reputation and location. They have always done great work on my car and I trust them when it comes to pushing the limits. They are definitely one of the leaders in testing new performance partsfor the Audi.I am on the list for the supercharger for the 4.2. But I know they are working with the actual RS6 turbos.

As for just putting GT turbos on the stock header. There looks like there would be several clearance issues not only that but at some point the stock header would become restrictive and could lead to a blown head gasket

ORIGINAL: HP Addict

ORIGINAL: HP Addict

umm last i checked the b5 rs4 had a 2.7 with 2 k04 turbos. im obvioulsy not comparing it to a N/A V8.

ORIGINAL: Baskin 4.2l

tsbpenguin


no offence taken I really didn't know you were referring to stock fueling all I saw was that GT turbos don't make more power than ko4's...you can look at a compressor map and see that is wrong (as compressor maps have hp figures in them)

Also the point that you can do a GT upgrade for the same as a ko4. Saving money by just putting on new flanges.. A GT turbo will not fit on a stock header (some one in australia tried this.) the compressor cover and turbo it self is almost twice the size. The flangeon a GT turbo is about21/4" square the header out let is about 1/2 that. you would need to step up the header flange side several times. after all that you don't have the location any more to fit the turbos in the location provided/Even if you did get the header rigged up you would still need

To custom make
oil lines in
oil lines out
coolant lines in
coolant lines out
fittings
relocate the EGT
Source the right restricted fittingsfor the oil lines to the turbos. Because the S4 has too high oil pressure and it will blow out the seals in the GT turbos
completely new Dp's
Making sure you put the 02's in the correct location
modify your current cat back
create some kind of turbo bracket. because a GT turbo probably weighs more as it is much bigger
inlet pipes both sides / with hoses and clamps
pressure side to innercooler piping / with hoses and clamps
turbo hose and vacuum line
Then either fab your own wastegates or use external...going external creates even more money and work. Fabricating your own wastegates looks hard enough on some of the RS6 turbo upgrades I have seen I would hate to see it for GT's

Everything you listed there is pretty simple cutting and welding. Stuff I can do myself. Parts cost for all that stuff is maybe 1000. Oil pressure regulator, some modified dp's, then you wouldn't need a modified catback as the dp's would be in stock location, you could still use stock IC route, just may need to modify a little where it meets the turbos. External wastegate is simple. I've done them before. So say the parts were 1500 (on the high side).

GT2871R's : $2200
^Those parts^: $1500
Injectors & Pump: $350
Total: $4050

Look we're still 1500 less than the k04 kit.

Then after you have the motor out for about 6 months tried to source all the parts spent hundreds of man hours to bolt turbos up to a restrictive stock header. You will still need tuning. If you are lucky to find some one to tune it for you. you are not going to get some one to tune the car for a stock fuel system/All this is if you can even get the turbos to fit in the area allowed

6 months are you kidding me? It would take a shop a week or me and a friend maybe 2-3. Sourcing the parts? It's all piping and general parts. Very easy to find. No one would tune it? Then why do a good few people run a gt28r setup?

You can't drive with stock tuning or slightly modified because the turbos are so different when you do give it any gas to accelerate you will get a negative boost code because the GT turbos are much slower to build boost as the ko3's even ko4's ramp up faster. Custom tune is well over 1000 $

I don't know where you get tuned for $1000 but you're getting ripped off. The shop i do dyno tuning at charges $80/hr for dyno tuning. They can have it perfectly dialed in, in about 3 hours. High side is 4 hours. That puts us at $320 for tuning.

Previous total: $4050
Tuning: $320
Total: $4370
Hmm still $1000 cheaper than the k04 kit? And tons more power.

Or you can get a kit ko4, RS6, GT for the money I don't think anyone can make it for less unless you take months or years. There is just too much time needed and too little room. Even if you hack it there are so many variables and so little room

and all you need to do to upgrade your fuel system to run big power is a fuel pump and injectors. FPR. then the tune


Lastly several BIG ko4 carsMADE 450+whp
and form what I know there are several GT cars well over 600whp